1. Field of the Invention
The present invention relates to a chemical liquid processing apparatus for processing a substrate using chemical liquid and a chemical liquid processing method therewith and more particularly to technology for processing various types of substrates such as a semiconductor substrate in semiconductor device manufacturing process, reticule (photo mask) in lithographic process which is one step of semiconductor device manufacturing process, and flat panel in liquid crystal display manufacturing process.
2. Description of the Related Art
Generally, chemical liquid processing for processing various types of substrates using chemical liquid is carried out by performing chemical liquid film forming step for forming chemical liquid by puddling on a processing object substrate, on which a processing object film is formed, so as to process the processing object film into a desired configuration, and liquid removing (cleaning/drying) step for cleaning and drying the processing object substrate on which the chemical liquid is applied, repeatedly. Meanwhile, the chemical liquid processing step mentioned here includes, for example, development processing in photo-lithographic step of semiconductor manufacturing process, wet etching processing to be carried out after photo-lithographic step and the like.
By the way, the aforementioned chemical liquid film forming step and liquid removing (cleaning/drying) step have following technical problems which should be solved.
First, technical problems in the chemical liquid film forming step will be described.
The chemical liquid film forming step for etching the processing object film by coating and settling the chemical liquid on the processing object substrate, on which the processing, object film is formed, has such a problem that supply of hew etchant to an etching region is not accelerated because etching product remains on the etching region and the surrounding of the etching region. As a result of this problem, etching velocity around the etching region is reduced. This problem is particularly conspicuous around the etching region near a broader etching region.
To solve this problem, some applications were proposed up to now. For example, Japanese Patent Application Laid-Open No. H11-329960 has disclosed a technology of moving chemical liquid on the processing object film at the time of etching. According to this document, a predetermined sheet material is brought into contact with the surface of chemical liquid on the processing object film and by moving that sheet material, the chemical liquid is moved on the processing object film. By moving the chemical liquid on the processing object film, a flow is generated in the chemical liquid so that the chemical liquid is agitated. As a result, new etchant is supplied to the etching region, thereby making it possible to suppress reduction of the etching velocity in the etching region near a broader etching region.
However, if such technology is employed, after the chemical liquid is agitated, the sheet material needs to be washed and when washing the sheet material, dust and dirt adhering to the sheet material adhere to the surface of the processing object substrate, so that a defect may occur on the processing object substrate.
On the other hand, according to other proposal, the chemical liquid is moved on the processing object film by rotating the processing object substrate intermittently (see Japanese Patent Application Laid-Open No. H11-307433). According to this technology, the processing object substrate is held by the substrate holding portion and by repeating a rotation and a static condition of the processing object substrate, the chemical liquid is moved.
However, as a result of investigation of this technology by inventors of the present invention, when the processing object substrate was rotated, the chemical liquid was not moved but rotated together with the processing object substrate because of its viscosity. And, when the rotation of the processing object substrate was stopped, the chemical liquid only trembles slightly due to its inertial force. Therefore, even if this technology is employed, the reduction of etching velocity in the etching region near a broader etching region must be difficult to suppress sufficiently.
As described above, the conventional chemical liquid film forming step cannot suppress the reduction of etching velocity in the etching region without generation of defects or additional work. Thus, the yield rate of the entire chemical liquid processing cannot be improved.
Next, technical problem of liquid removing (cleaning/drying) step will be described.
In a conventional liquid removing (cleaning/drying) step, cleaning chemical liquid on the substrate is blown out and removed by rotating the substrate at high speeds.
However, when the liquid removing (cleaning/drying) step is carried out by this method, the quantity of defects induced by microscopic dust generated from abrasion between a chuck for fixing the substrate and a rear face of the substrate is increased with decrease of pattern dimension and increase of rotation speed. Further, because of increases of aspect ratio of resist pattern and diameter of the substrate with micro-fabricated resist pattern in recent years, influences by water flow and centrifugal force generated at high speed rotation increase, so that pattern fall is more likely to occur. Thus, in the conventional liquid removing (cleaning/drying) step, the yield rate of the entire chemical liquid processing cannot be improved like the chemical liquid film forming step.
As described above, the conventional chemical liquid processing apparatus and chemical-liquid processing method have technical problems which should be solved early in both the chemical liquid film forming step and liquid removing (cleaning/drying) step. Thus, it is difficult to improve the yield rate of the entire chemical liquid processing.